Within the field of metal cutting operations, there are known many milling cutters having cutting inserts with serrated cutting edges, which enable higher metal removal rates as compared with cutting inserts having non-serrated cutting edges. However, this is achieved at the expense of rougher surface finish. In order to improve the surface finish, the cutting inserts are mounted on the milling cutter with the serrations of consecutive cutting inserts offset, or out of phase, in relation to each other. Examples of tools with such cutting inserts can be found in U.S. Pat. Nos. 3,574,911, 3,636,602 and 3,875,631. Nevertheless, these types of cutting tools suffer from a disadvantage in that the axially forward most serration of the operative cutting edge of the axially forward most cutting insert (i.e. the cutting insert which is closest the face of the milling cutter) is more exposed than the other serrations of that cutting insert and than the serrations of the other cutting inserts, and therefore is exposed to wear and is vulnerable to breakage.
A solution to this deficiency, as suggested by several tool manufacturers, is to provide an external member to support the exposed serration. For example, U.S. Pat. No. 3,701,187 discloses ribbed cutting inserts spaced angularly around the periphery of a supporting disk that are staggered relative to one another along the axis of the disk to remove laterally spaced chips from the bottom of the slot, while the sides of the slot are face milled by side cutting inserts spaced angularly from the ribbed inserts. However, the additional side cutting inserts lead to unnecessary operation costs which could be saved. For example, replacement of the cutting inserts is a task that is substantially time consuming and requires additional tools for operating the process, especially if the additional cutting inserts are not identical to the ribbed cutting inserts. Furthermore, the additional cutting inserts are a redundant expense. Therefore, such a solution is, of course, money, labor and time consuming.